Rectifier.



'V'. M. HARRIS.

REGTIFIER.

APPLICATION FILED AUG. 24, 1912.

1,1 l 9,95 l Patented De0.8,1914.

2 SHEETS-SHEET 1.

jaaa/@Z377 Y. M. HARRIS. RBGTIFIIIR. APPLICATION FILED AUG. 24, 1912.

1,1 1 9,95 1. Patented Dee. s,- 1914.

2 SHEETS-SHEET 2.

UNITED STATES PATENT OFFICE.

VARIAN M. HARRIS, 0F GHEGAGG, ILLINOIS, ASSIGNOB, TO HENRY S. HAWLEY, TRUSTEE, OF CHICAGO, ILLINOIS.

.RECTIFIER Specicaton of Letteijslatent.

Patented Dec. 8, 1914.

Application led A ugust 24, 19,12. Serial No. 716.807.

To aZZ whom it may. concern Be it known that I, VARIAN M. HARRIS,- a citizen of the United States, residing at Chicago, in the county of Cook andl State of Illinois, have invented certain :new and useful Improvements in Rectifiers, of which the following is a specication.

My invention relates to rectifiers, and' refers Vparticularly to the class ofso-called mechanical rectifiers for changing alternating current into pulsating unidirectional current, or vice versa.

I am aware that mechanical rectifiers have been used in the past, but these proved unsatisfactory on account of the fact that no provision was made forvcutting the wave phases of the alternating current at absolutely uniform points in converting the alternating into unidirectional current. The lack of means for compensatin for the variations in the wave phases o alternating current lines has heretofore been a cause of great difficulty in theoperation of mechanical rectifiers.

It is the object of my invention to provide means for compensating for current variations in the main line, and in this way to insure a uniform and correct cutting of the Wave phases in converting the alternating into unidirectional current.

The motor which forms a part of my invention has its field element and rotor maintained in perfect synchronous relation by means hereinafter described, and in this way the current-converting, or rectifying means which is used is. enabled to operate accurately and efiiciently.,

These and other advantages of myinvention will be more readily understood by reference to the accompanying drawings, which represent a preferred embodiment of my invention, and in .which- Figure 1 is a side elevation of my motor and rectifier, and Fig. .2 is a plan of the apparatus shown in Fig.` 1.

My improved motor is carried by a bracket 10, which is suitably fastened to a panel 11 by means ofthe bolts 12. The field element consists of a casing 13 provided with an upper spider 14 and a lower s ider 15. To the upper spider 14 is attac ed Vthe bearing member '16 having an aperture 17, which is engaged by the end (if the bearing lscrew 1 8, theM latter being locked in adjusted 'position by the nut 19.` The lower v'spider 15 is pro vided with the bearmg member 20, having the recess 21 into which the beveled end 23a of the screw 24 projects, thereby supporting the field element. The screw 24 1s locked 1n position by the nut 25. It will thus be apparent that the field element as a whole. with its spiders 14 and 15, is freely oscilla-A tory on an axis which passes through the screws 18. and 24.

The field casing 13 is provided with a series of alternate poles 26 and a second series of poles 27, these poles having the pole faces 28 and 29, respectively. 'Each of the poles 26 and 27 is provided with windings in the usual manner, which are connected with each other and by the conductors 30 and 31 with a source of single-phase alternating current. The poles 26 and 27 are so wound that the polarity of all of the alternate poles 26 is the same, while at the same time the poles 27" have the opposite polarity. On account of the alternations of the main current, the polarity of all of these poles is, of course, constantly changing.

The rotor shaft 22 has a beveled end 22a, which is supported in the'i'ecess 22b in the bearing block 22e of the bearing member 20, and on the opposite end the shaft 22 has its bearing in the bearing member 32 supported on or made integral with the upper spider 14. The upper end of the rotor shaft 22 is in line with the screw 18, thereby making the field element and the rotor coaxial. Mounted on the rotor shaft 22 is the rotor 33 consisting of a plurality of laminae 33a,

of steel or other suitable metal, these laminae being insulated from each other in the usual manner. The laminae are formed with' a plurality of alternate pole facessl 3.4 i and 35. Also mounted on the rotor shaft 22 is the commutator 36 having a plurality of segments 37 and 38, these segments being insulated from each other by the portions 39 of the commutator. .The

number of segments in the commutator 36 is Z."'.`

referably the same as the number of pole faces o f the rotor and the number of pole faces of the field element. Also mounted on the rotor shaft 22 are the slip rings 40 and 42`of insulating material.A One o f the slip rings, as, for example, 40, is electrically connected 'with alternate commutator segments 38, While Ythe other slip ring, as, for example, 41, is' similarly connected with the other se- 41, separated from eachother by the section ries of commutator segments 37. The slip ring 40 is engaged by the brush 43'held bythe brush holder 44 attached tov thespider;

14, and the brush 45 engages the slip ring 47, which is held by thebrush helder, 48, which, in tur-n, is carried by the"s`pider' 14.

Alo Similarly, the brush 49 also engages the commutator 36. The brush 49 is'carried by the vbrush holder 50, whichis supported on the spider 14. The brushes 47 and 49 are so positioned that while the brush 47for exl ample,^-engages one of the commutator segments 37, the brush 49 will engage onel of the segments 38. Having thus described the construction of the various parts which areused invmy invention, the operation of the same may noW be readily understood: The rotor is first brought up to speed by any suitable .starting device. Such starting device forms no part of the present invention. When the rotor'is thus rotating, -it is kept at speed and in synchronism witlrthe main current by the magnetic attraction exerted by the pole faces28 and 29 ofthe field element on the pole faces @and 8,5of'the rotor. In order to clearly 30 understand this action, let us assume that the pole faces 34 and 35 are, midway between acent pole faces 28 and 29 of the field .element. The wave phase. of, the alternating current is nowat its maximum point.l If the rotor were at restit will be evident that the-magnetic attraction exerted by ,the vaf rious polefa'ces of the fieldvelement would exactly counterbalance each other, sozthat there would be no rotation of the rotor. On 40 the other `hand,.since the rotor has already been brought up to speed by some suitable device, the inertia ofthe rotor carries the pole faces of the rotor toward the pole faces of the -ield element., -As this action takes place, the wave phase vgradually decreases until, 4when ther pole faces of the rotor are exactly opposite the pole faces of the-field Lelement, the neutralpoint ofthe wave phase -is' reached. The inertia of the rotor con- ,tinues to carry it around, however, and this inertia overcomes .the (magnetic attraction exerted by the pole'faces of the field element until the polefaces of the rotor reach a 'position midway between the pole faces ofthe y field element. Whenfthe pole` faces .of ythe ,rotor pass these positions, however, the magnetic attraction of the pole facesof the field element again attracts the pole faces of the rotor inthe direction of rotation, and the speed ofthe rotor is'thusmaintained. Now,l

let us assume Uthat a mechanically fixed field element were used. If the frequency of the cycles of the main line should become greater than normal, the neutral points of 55 the wave phases would be reached before the -elfect of this would be to give the rotor a slightly greater impetus and to, increase-f its speed, and thereby bring it into exact syn- 'chronism with the 'a'lternations of the main line. w75

The conditions. which lia'vejustbeen described would take place 'with a me chani cally fixed eld element, providedzthe waves were in, the form ofa true sine curve. It is welLknownj, however, thI-'t lommercial sources of alternatingcurrent. do not generate waves.V in. the formjI of, true'- sine. curves, so that ineorder-.to maintain theretorl of a motor in exact fsynchronis'm with the 'alternating current with which the field element of said motor is supplied, compensation must .bemade 'for the inequalities'pf 'the shapes of the'waves. I accornplish this result by the free oscillation of the field elev ment. i Withsuch ,af freely oscillatory eld elementfduring operation ,ofthe machine this field, element would tend tol rotatelir'il a direction .opposite to the v direction of rotation of the rotor zby, reason,of the mutual at, traction ,betweenf th'se elements; In he present` embodiment f of my invention vvt tendency is counteracted' by mounting the bearings of thel rotor in the fieldelerr'len't itself, and also by, the .frictional mounting of the 'field element,so that the friction of thebearings, theinertia of the field element, and the.-,windage' of the rotor (tending to rotate the .field elementlin the same direction as the rotation of the rotor) cause vthe field element to .remain substantially the same position during the operation of themachine.` On account of `the factthat the rfieldelement is -freely oscillatory,I however, any variationsi'n `the current supply to this elementfcauses thelatter to"r otat`e slightly in one-direction or the other to maintain a perfect synchronous relation ybetween the alternatin `current supplied tO the field 61- ment an theroton Although I have mentioned theibearingsin the fieldfelement as one of the frictional means for retarding the rotation .of the eld element, lother means couldbe used for the same purpose; for example,'resilient'stops, or the', like, suchas shownin y copendiiig application Serial no ico rot

`Passing now to a .description of the. op,- eration of the-current vconverting means of my rectier, `,current from the main source f- .ofalternating current is introduced into the brushes 43 -and45 through suitable conductors, the current passing zthrough the conductors 30 and 31 to the eld'element being in the form of a shunt from the main conductors. The current passing through the the same nature as brush 45, for example, next passes through the slip ring 4l to the segments 37, and then out through the brush 49, which, we will assume, is engaging one of the segments 37, through a conductor attached to said brush. Similarly, at the same instant (assuming the circuit in which the brushes 47 and 49 are included to be closed) current of the opposite polarity will pass from brush 47 to segments 38 and then to brush 43, thereby completing the circuit with the source of alternating current.

`It will now be apparent that if the rotor were stationary, the current passing through the conductors attached to the brushes 47 and 49 would be alternating and of exactly the current passing through the brushes 43 and 45. The rotor,

- Jfrom the spirit or scope of however, is rotating in exact synchronism with the main current, a small proportion of which is supplied to the windings of the field element, so that while the brush 49, for example, is in engagement with a segment 37 during one phase of the alternatlon of the main line, when the next phase takes place a commutator segment 38 is brought into Contact with the brush 49, so that the pulsations passing out through the brush 49 are always of one polarity, while the pulsations passing out through the brush 47 are similarly always of the opposite polarity. By having the briishes 47 mounted on the oscillatory field element, these waves are always cut at compensation for the irregularity of form of the waves is made.

It will be apparent to those skilled in the art that many changes could be made in ine detailed construction of the apparatus which I have described without departing my invention. `What I claim is:

l. An alternating current rectifier, comprising the combination of a rotor, a field element, means for mounting said field element for oscillatory motion, a commutator rotatable with said rotor, means for conducting alternating current to said commutator, and means for carrying the rectified current away from said commutator, substantiallyas described.

2. An alternating current rectifier, comprising the combination of a rotor, a field exactly the right point, and

element, means for mounting said field element for oscillatory motion, means for eX- citing the poles of said field element from a source of alternating current, a commutator rotatable with said rotor, said commutator comprising a pair of segments insulated from each other, means for conducting the current to said segments from said source, and means for carrying current away from said segments, whereby, during rotation of said rotor in synchronism with said source, the current passing into said commutator will be changed from alternating to unidirectional, substantially as described.

3. In a rectifier, the combination of a field element, means for mounting said field elcment for oscillatory motion, a rotor mounted with its bearings in said field element, a commutator rotatable with said rotor, Saud commutator having a pair of segments 1nsulated from each other, electrically 00nducting means connected with each of sald segments, and a brush for engaging each of said segments, said brushes being mounted on said field element, substantially aS d6- scribed'.

4. 'An alternating current rectifier, cumprising the combination of a rotor, a field element, means for mounting said field element for oscillatory motion, meansfor exciting ythe poles of said field element from a source of' alternating current, a commutator rotatable with said rotor, said commutator comprising a pair of segments insulated from each other, a slip ring electrically C011- nected to each of said segments, a brush e11- gaging each of said segments, said brushes being mounted on and movable with said field element whereby during rotation -Of said rotor in synchronism with said source said brushes are adjusted to compensate for variations lin the wave phases of said current, and a brush engaging each of said slip rings whereby the alternating current passing through one set of brushes to said commutator will be conducted through the other set of brushes from said commutator as unidirectional current, substantially as described.

VARIAN M. HARRIS. Witnesses:

HENRY M. I-IUxLEY, T. D. BUTLER. 

